/*
 * Copyright 2013 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.praisehim.koraildelay.SwipeLibrary;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ValueAnimator;
import android.annotation.SuppressLint;
import android.graphics.Rect;
import android.util.Log;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.ListView;

public class DismissSwipeListViewTouchListener implements View.OnTouchListener
{
	// Cached ViewConfiguration and system-wide constant values
	private int mSlop;
	private int mMinFlingVelocity;
	private int mMaxFlingVelocity;
	private long mAnimationTime;

	// Fixed properties
	private ListView mListView;
	private OnSwipeCallback mCallback;
	private int mViewWidth = 1; // 1 and not 0 to prevent dividing by zero
	private boolean dismissLeft = true;
	private boolean dismissRight = true;

	// Transient properties
	public List<PendingSwipeData> mPendingSwipes = new ArrayList<PendingSwipeData>();
	private int mDismissAnimationRefCount = 0;
	private float mDownX;
	private boolean mSwiping;
	private VelocityTracker mVelocityTracker;
	private int mDownPosition;
	private View mDownView;
	private boolean mPaused;

	/**
	 * The callback interface used by {@link SwipeListViewTouchListener} to
	 * inform its client about a successful swipe of one or more list item
	 * positions.
	 */
	public interface OnSwipeCallback
	{
		/**
		 * Called when the user has swiped the list item to the left.
		 * 
		 * @param listView
		 *            The originating {@link ListView}.
		 * @param reverseSortedPositions
		 *            An array of positions to dismiss, sorted in descending
		 *            order for convenience.
		 */
		void onSwipeLeft(ListView listView, int[] reverseSortedPositions);

		void onSwipeRight(ListView listView, int[] reverseSortedPositions);
	}

	/**
	 * Constructs a new swipe-to-action touch listener for the given list view.
	 * 
	 * @param listView
	 *            The list view whose items should be dismissable.
	 * @param callback
	 *            The callback to trigger when the user has indicated that she
	 *            would like to dismiss one or more list items.
	 */
	public DismissSwipeListViewTouchListener(ListView listView,
			OnSwipeCallback callback)
	{
		ViewConfiguration vc = ViewConfiguration.get(listView.getContext());
		mSlop = vc.getScaledTouchSlop();
		mMinFlingVelocity = vc.getScaledMinimumFlingVelocity();
		mMaxFlingVelocity = vc.getScaledMaximumFlingVelocity();
		mAnimationTime = listView.getContext().getResources()
				.getInteger(android.R.integer.config_shortAnimTime);
		mListView = listView;
		mCallback = callback;
	}

	/**
	 * Constructs a new swipe-to-action touch listener for the given list view.
	 * 
	 * @param listView
	 *            The list view whose items should be dismissable.
	 * @param callback
	 *            The callback to trigger when the user has indicated that she
	 *            would like to dismiss one or more list items.
	 * @param dismissLeft
	 *            set if the dismiss animation is up when the user swipe to the
	 *            left
	 * @param dismissRight
	 *            set if the dismiss animation is up when the user swipe to the
	 *            right
	 * @see #SwipeListViewTouchListener(ListView, OnSwipeCallback, boolean,
	 *      boolean)
	 */
	public DismissSwipeListViewTouchListener(ListView listView,
			OnSwipeCallback callback, boolean dismissLeft, boolean dismissRight)
	{
		this(listView, callback);
		this.dismissLeft = dismissLeft;
		this.dismissRight = dismissRight;
	}

	/**
	 * Enables or disables (pauses or resumes) watching for swipe-to-dismiss
	 * gestures.
	 * 
	 * @param enabled
	 *            Whether or not to watch for gestures.
	 */
	public void setEnabled(boolean enabled)
	{
		mPaused = !enabled;
	}

	/**
	 * Returns an {@link android.widget.AbsListView.OnScrollListener} to be
	 * added to the {@link ListView} using
	 * {@link ListView#setOnScrollListener(android.widget.AbsListView.OnScrollListener)}
	 * . If a scroll listener is already assigned, the caller should still pass
	 * scroll changes through to this listener. This will ensure that this
	 * {@link SwipeListViewTouchListener} is paused during list view
	 * scrolling.</p>
	 * 
	 * @see {@link SwipeListViewTouchListener}
	 */
	public AbsListView.OnScrollListener makeScrollListener()
	{
		return new AbsListView.OnScrollListener()
		{
			@Override
			public void onScrollStateChanged(AbsListView absListView, int scrollState)
			{
				setEnabled(scrollState != AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL);
			}

			@Override
			public void onScroll(AbsListView absListView, int i, int i1, int i2)
			{

			}
		};
	}

	@SuppressLint("NewApi")
	@Override
	public boolean onTouch(View view, MotionEvent motionEvent)
	{
		if (mViewWidth < 2)
		{
			mViewWidth = mListView.getWidth();
		}

		switch (motionEvent.getActionMasked())
		{
		case MotionEvent.ACTION_DOWN:
		{
			if (mPaused)
			{
				return false;
			}

			// TODO: ensure this is a finger, and set a flag

			// Find the child view that was touched (perform a hit test)
			Rect rect = new Rect();
			int childCount = mListView.getChildCount();
			int[] listViewCoords = new int[2];
			mListView.getLocationOnScreen(listViewCoords);
			int x = (int) motionEvent.getRawX() - listViewCoords[0];
			int y = (int) motionEvent.getRawY() - listViewCoords[1];
			View child;
			for (int i = 0; i < childCount; i++)
			{
				child = mListView.getChildAt(i);
				child.getHitRect(rect);
				if (rect.contains(x, y))
				{
					mDownView = child;
					break;
				}
			}

			if (mDownView != null)
			{
				mDownX = motionEvent.getRawX();
				mDownPosition = mListView.getPositionForView(mDownView);

				mVelocityTracker = VelocityTracker.obtain();
				mVelocityTracker.addMovement(motionEvent);
			}
			view.onTouchEvent(motionEvent);
			return true;
		}

		case MotionEvent.ACTION_UP:
		{
			if (mVelocityTracker == null)
			{
				break;
			}

			float deltaX = motionEvent.getRawX() - mDownX;
			mVelocityTracker.addMovement(motionEvent);
			mVelocityTracker.computeCurrentVelocity(500); // 1000 by defaut but
															// it was too much
			float velocityX = Math.abs(mVelocityTracker.getXVelocity());
			float velocityY = Math.abs(mVelocityTracker.getYVelocity());
			boolean swipe = false;
			boolean swipeRight = false;
			
			Log.i("MinX", String.valueOf(mMinFlingVelocity));
			Log.i("speedX", String.valueOf(velocityX));
			Log.i("speedY", String.valueOf(velocityY));
			
			if (Math.abs(deltaX) > (float) mViewWidth / 1.7)
			{
				swipe = true;
				swipeRight = deltaX > 0;
			}
			else if (mMinFlingVelocity+100 <= velocityX
					&& velocityX <= mMaxFlingVelocity && velocityY < velocityX)
			{
				swipe = true;
				swipeRight = mVelocityTracker.getXVelocity() > 0;
			}
			if (swipe)
			{
				// sufficent swipe value
				final View downView = mDownView; // mDownView gets null'd before
													// animation ends
				final int downPosition = mDownPosition;
				final boolean toTheRight = swipeRight;
				++mDismissAnimationRefCount;
				mDownView.animate()
						.translationX(swipeRight ? mViewWidth : -mViewWidth)
						.alpha(0).setDuration(mAnimationTime)
						.setListener(new AnimatorListenerAdapter()
						{
							@Override
							public void onAnimationEnd(Animator animation)
							{
								performSwipeAction(downView, downPosition,
										toTheRight, toTheRight ? dismissRight
												: dismissLeft);
							}
						});
			}
			
			else
			{
				// cancel
				mDownView.animate().translationX(0).alpha(1)
						.setDuration(mAnimationTime).setListener(null);

				
			}
			mVelocityTracker = null;
			mDownX = 0;
			mDownView = null;
			mDownPosition = ListView.INVALID_POSITION;
			mSwiping = false;
			break;
		}

		case MotionEvent.ACTION_MOVE:
		{
			if (mVelocityTracker == null || mPaused)
			{
				break;
			}

			mVelocityTracker.addMovement(motionEvent);
			float deltaX = motionEvent.getRawX() - mDownX;
			if (Math.abs(deltaX) > mSlop)
			{
				mSwiping = true;
				mListView.requestDisallowInterceptTouchEvent(true);

				// Cancel ListView's touch (un-highlighting the item)
				MotionEvent cancelEvent = MotionEvent.obtain(motionEvent);
				cancelEvent
						.setAction(MotionEvent.ACTION_CANCEL
								| (motionEvent.getActionIndex() << MotionEvent.ACTION_POINTER_INDEX_SHIFT));
				mListView.onTouchEvent(cancelEvent);
			}

			if (mSwiping)
			{
				mDownView.setTranslationX(deltaX);
				mDownView.setAlpha(Math.max(0.3f, Math.min(1f, 1f - 2f * Math.abs(deltaX) / mViewWidth)));
				return true;
			}
			break;
		}
		}
		return false;
	}

	class PendingSwipeData implements Comparable<PendingSwipeData>
	{
		public int position;
		public View view;

		public PendingSwipeData(int position, View view)
		{
			this.position = position;
			this.view = view;
		}

		@Override
		public int compareTo(PendingSwipeData other)
		{
			// Sort by descending position
			return other.position - position;
		}
	}

	private void performSwipeAction(final View swipeView,
			final int swipePosition, boolean toTheRight, boolean dismiss)
	{
		// Animate the dismissed list item to zero-height and fire the dismiss
		// callback when
		// all dismissed list item animations have completed. This triggers
		// layout on each animation
		// frame; in the future we may want to do something smarter and more
		// performant.

		final ViewGroup.LayoutParams lp = swipeView.getLayoutParams();
		final int originalHeight = swipeView.getHeight();
		final boolean swipeRight = toTheRight;

		ValueAnimator animator;
		if (dismiss)
			animator = ValueAnimator.ofInt(originalHeight, 1)
					.setDuration(mAnimationTime);
		else
			animator = ValueAnimator.ofInt(originalHeight, originalHeight - 1)
					.setDuration(mAnimationTime);

		animator.addListener(new AnimatorListenerAdapter()
		{
			@Override
			public void onAnimationEnd(Animator animation)
			{
				--mDismissAnimationRefCount;
				if (mDismissAnimationRefCount == 0)
				{
					// No active animations, process all pending dismisses.
					// Sort by descending position
					Collections.sort(mPendingSwipes);

					int[] swipePositions = new int[mPendingSwipes.size()];
					for (int i = mPendingSwipes.size() - 1; i >= 0; i--)
					{
						swipePositions[i] = mPendingSwipes.get(i).position;
					}
					if (swipeRight)
						mCallback.onSwipeRight(mListView, swipePositions);
					else
						mCallback.onSwipeLeft(mListView, swipePositions);

					ViewGroup.LayoutParams lp;
					for (PendingSwipeData pendingDismiss : mPendingSwipes)
					{
						// Reset view presentation
				//		pendingDismiss.view.setAlpha(1f);
				//		pendingDismiss.view.setTranslationX(0);
						lp = pendingDismiss.view.getLayoutParams();
						lp.height = originalHeight;
						pendingDismiss.view.setLayoutParams(lp);
						
						
						pendingDismiss.view.animate().translationX(0).alpha(1)
						.setDuration(mAnimationTime).setListener(null);		
					}

					mPendingSwipes.clear();
				}
			}
		});

		animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()
		{
			@Override
			public void onAnimationUpdate(ValueAnimator valueAnimator)
			{
				lp.height = (Integer) valueAnimator.getAnimatedValue();
				swipeView.setLayoutParams(lp);
			}
		});

		mPendingSwipes.add(new PendingSwipeData(swipePosition, swipeView));
		animator.start();
	}
}